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/* lzo1f_d.ch -- implementation of the LZO1F decompression algorithm
This file is part of the LZO real-time data compression library.
Copyright (C) 1996-2014 Markus Franz Xaver Johannes Oberhumer
All Rights Reserved.
The LZO library is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
The LZO library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with the LZO library; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Markus F.X.J. Oberhumer
<markus@oberhumer.com>
http://www.oberhumer.com/opensource/lzo/
*/
#include "lzo1_d.ch"
/***********************************************************************
// decompress a block of data.
************************************************************************/
LZO_PUBLIC(int)
DO_DECOMPRESS ( const lzo_bytep in , lzo_uint in_len,
lzo_bytep out, lzo_uintp out_len,
lzo_voidp wrkmem )
{
lzo_bytep op;
const lzo_bytep ip;
lzo_uint t;
const lzo_bytep m_pos;
const lzo_bytep const ip_end = in + in_len;
#if defined(HAVE_ANY_OP)
lzo_bytep const op_end = out + *out_len;
#endif
LZO_UNUSED(wrkmem);
*out_len = 0;
op = out;
ip = in;
while (TEST_IP_AND_TEST_OP)
{
t = *ip++;
if (t > 31)
goto match;
/* a literal run */
if (t == 0)
{
NEED_IP(1);
while (*ip == 0)
{
t += 255;
ip++;
TEST_IV(t);
NEED_IP(1);
}
t += 31 + *ip++;
}
/* copy literals */
assert(t > 0); NEED_OP(t); NEED_IP(t+1);
#if (LZO_OPT_UNALIGNED32)
if (t >= 4)
{
do {
UA_COPY4(op, ip);
op += 4; ip += 4; t -= 4;
} while (t >= 4);
if (t > 0) do *op++ = *ip++; while (--t > 0);
}
else
#endif
do *op++ = *ip++; while (--t > 0);
t = *ip++;
while (TEST_IP_AND_TEST_OP)
{
/* handle matches */
if (t < 32)
{
m_pos = op - 1 - 0x800;
m_pos -= (t >> 2) & 7;
m_pos -= *ip++ << 3;
TEST_LB(m_pos); NEED_OP(3);
*op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++;
}
else
{
match:
if (t < M3_MARKER)
{
m_pos = op - 1;
m_pos -= (t >> 2) & 7;
m_pos -= *ip++ << 3;
t >>= 5;
TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
goto copy_match;
}
else
{
t &= 31;
if (t == 0)
{
NEED_IP(1);
while (*ip == 0)
{
t += 255;
ip++;
TEST_OV(t);
NEED_IP(1);
}
t += 31 + *ip++;
}
NEED_IP(2);
m_pos = op;
#if (LZO_OPT_UNALIGNED16) && (LZO_ABI_LITTLE_ENDIAN)
m_pos -= UA_GET_LE16(ip) >> 2;
ip += 2;
#else
m_pos -= *ip++ >> 2;
m_pos -= *ip++ << 6;
#endif
if (m_pos == op)
goto eof_found;
}
/* copy match */
TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
#if (LZO_OPT_UNALIGNED32)
if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4)
{
UA_COPY4(op, m_pos);
op += 4; m_pos += 4; t -= 4 - (3 - 1);
do {
UA_COPY4(op, m_pos);
op += 4; m_pos += 4; t -= 4;
} while (t >= 4);
if (t > 0) do *op++ = *m_pos++; while (--t > 0);
}
else
#endif
{
copy_match:
*op++ = *m_pos++; *op++ = *m_pos++;
do *op++ = *m_pos++; while (--t > 0);
}
}
t = ip[-2] & 3;
if (t == 0)
break;
/* copy literals */
assert(t > 0); NEED_OP(t); NEED_IP(t+1);
do *op++ = *ip++; while (--t > 0);
t = *ip++;
}
}
#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP)
/* no EOF code was found */
*out_len = pd(op, out);
return LZO_E_EOF_NOT_FOUND;
#endif
eof_found:
assert(t == 1);
*out_len = pd(op, out);
return (ip == ip_end ? LZO_E_OK :
(ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
#if defined(HAVE_NEED_IP)
input_overrun:
*out_len = pd(op, out);
return LZO_E_INPUT_OVERRUN;
#endif
#if defined(HAVE_NEED_OP)
output_overrun:
*out_len = pd(op, out);
return LZO_E_OUTPUT_OVERRUN;
#endif
#if defined(LZO_TEST_OVERRUN_LOOKBEHIND)
lookbehind_overrun:
*out_len = pd(op, out);
return LZO_E_LOOKBEHIND_OVERRUN;
#endif
}
/*
vi:ts=4:et
*/
|
